util.py

# Fix Warmup Bug
from warmup_scheduler import GradualWarmupScheduler  # https://github.com/ildoonet/pytorch-gradual-warmup-lr


class GradualWarmupSchedulerV2(GradualWarmupScheduler):
    def __init__(self, optimizer, multiplier, total_epoch, after_scheduler=None):
        super(GradualWarmupSchedulerV2, self).__init__(optimizer, multiplier, total_epoch, after_scheduler)
    def get_lr(self):
        if self.last_epoch > self.total_epoch:
            if self.after_scheduler:
                if not self.finished:
                    self.after_scheduler.base_lrs = [base_lr * self.multiplier for base_lr in self.base_lrs]
                    self.finished = True
                return self.after_scheduler.get_lr()
            return [base_lr * self.multiplier for base_lr in self.base_lrs]
        if self.multiplier == 1.0:
            return [base_lr * (float(self.last_epoch) / self.total_epoch) for base_lr in self.base_lrs]
        else:
            return [base_lr * ((self.multiplier - 1.) * self.last_epoch / self.total_epoch + 1.) for base_lr in self.base_lrs]